 ?Bach Alive in the Nation’s Library.? The Washington Bach Consort. Cantata BWV 10, ?Meine Seel’ erhebt den Herren,? Barber’s ?Agnus Dei? and other works in the Library archives. 8 p.m. April 15. Free, but tickets required, through Ticketmaster only, with a handling fee. Limit two tickets per person. 800/551-7328.

 David Cates, harpsichord. Bach’s Partita in D Major and the English Suite in G minor. 8 p.m. April 22. Free, but tickets required, through Ticketmaster only, with a handling fee. Limit two tickets per person. 800/551-7328.